Existing software systems running on a computer allow a user to design a dental restoration, such as a cap, which fits over a tooth stump, or a pontic, which replaces a missing tooth and attaches to adjacent teeth stumps. A model of the dental restoration is then milled from a blank, which is, for example, a cube or cylinder of a ceramic material. The blanks, and the milling machine, have size limits, and the user may go through a lengthy design process to find her dental restoration exceeds the size limits.
One approach to determining of size of the blank in advance of design is to use a plastic apparatus with an area corresponding to an available blank's size removed. The plastic apparatus may be transparent. A user may then physically place the apparatus over a model of the tooth stump and try to determine the appropriateness of the size of the blank. This is technique is imprecise and does not account for eventual build-up of the dental restoration.
Another approach is to check the size of the dental restoration after the design is completed, just before milling. The size of the design, it may be found, is incompatible with the size of the blank, and the user must then redesign the dental restoration.